1. Field of the Invention
The present invention is in the field of textile equipment, and, more particularly, concerns a safety apparatus for a traveling unit or device of a textile machine and a method of operating such textile machine.
In a particularly advantageous environment of use of the present invention, such relates to bale opener or opening apparatus provided with safety apparatus or equipment for minimizing risks that foreign objects, meaning not only inanimate objects but also human beings, such as especially the hands or other parts of machine operating personnel, will come into contact with rapidly rotating or moving components of the textile machine. Still further, the invention is especially, although not exclusively concerned, with safety or protective apparatuses or devices constructed and arranged to prevent entry of objects into the zone occupied by opening rollers of opening members of cotton bale openers or bale opening machines and to sensing systems for detecting in advance objects moving toward such zones, so that the opening rollers or the bale opening machines may be stopped before damage is done. The present invention is capable of specifically providing protection in zones laterally below, frontally below and directly below the opening member of a bale opener or bale opening machine.
2. Discussion of the Background and Material Information
Textile fiber raw material and, in particular, raw cotton is usually delivered in bale form. In a fiber processing operation prior to spinning, the raw cotton material must be brought into the form of loose flocks and in this state the material is subsequently cleaned and the individual fibers are stretched and rendered parallel to one another in a carding process.
Bale opening machines, which open such bales, typically contain a machine frame equipped with traveling wheels which is moved back and forth upon essentially straight rails along a limited bale opening path. At one side of the machine frame there is mounted the opening member in a direction extending transversely with respect to the essentially straight rails such that the opening member can be elevationally displaced. The bales to be opened are arranged in rows substantially parallel to the essentially straight rails and the opening member is moved back and forth over the top surface of the erected bale row in order to remove the fiber material in the form of fiber flocks.
The opening member possesses one or more drivable opening rollers arranged such that their rotational axes are disposed horizontal and substantially perpendicular to the direction of movement of the bale opening machine. These opening rollers are encased in a casing or housing which is open towards the top and laterally enclosed at all sides, however open towards the bottom. During opening of the bales this downwardly directed or lower opening of the casing or housing is essentially closed off by the top surface of the bales, so that the opening rollers present no danger to the machine operators or other objects. Nonetheless, danger zones or areas exist around the vicinity of the bale opening machine, especially when processing irregular bale rows. Under these circumstances, the opening rollers constitute a real danger during their rotation and when the lower opening of the housing is not completely shielded. A machine operator or other individual and also an inanimate object can enter from below or at an inclination from below through the lower opening and inadvertently contact the opening rollers, resulting in the occurrence of an accident.
More specifically, loosening of the bale-like raw material and the successive delivery thereof to the cleaning and carding means are generally performed through the layerwise opening up of the bales using the bale opening machine containing, as stated, one or more of such rapidly rotating opening rollers equipped, for instance, with tearing pins. As also previously explained, such bale opening machines or bale openers are, for example, provided with the opening member which is passed from above over the row of the raw textile bales. By moving the opening member backwards and forwards over the bale row with simultaneous lowering thereof, the raw fiber material is removed layer-by-layer by the opening roller or rollers, as the case may be. The thus obtained fiber flocks are supplied to a subsequent processing means as a flock stream by a ventilator or fan.
The exposed parts of the rapidly rotating opening roller or rollers can constitute a hazard for the machine operator, particularly if the operator does not exercise sufficient care when working on or around the bale opening machine. This danger occurs if the area of the bale opening machine which is open towards the bottom of the opening roller or roller is not completely and directly located over and in contact with the bale to be processed. For example, this is the case when the opening member has reached the end of the bale row, if a bale row with bales of unequal height are processed, or if the dimensions of the bales do not completely shield the opening roller or rollers.
As is known in this art, danger zones or areas either can be fenced off by mechanical barriers, so that access thereto is not possible and/or at locations where such access or entry is possible, there can be used monitoring or surveillance barriers which produce an alarm in the event of unwanted access or entry. Upon giving of such alarm the danger event is, for example, shutdown. Specifically, in the case of a bale opening machine the bale opening rollers are typically stopped, thereby eliminating any danger therefrom.
Furthermore, according to the prior art, the inherent danger of rotating bale opening rollers, in those cases where they are not screened off or shielded, is counteracted in basically two different ways: the first technique employs a stationary barrier or fence around the entire row of bales, in other words, there is fenced off the entire region or space through which the potentially dangerous bale opening roller or rollers travel, or else there can be employed a barrier or guard which essentially co-travels with the potentially dangerous bale opening roller or rollers and surrounds the immediate vicinity of such bale opening roller or rollers.
A stationary barrier or fence which encircles the entire region through which the bale opening member moves has been disclosed, for instance, in the German Patent No. 3,032,584, published Mar. 11, 1982. Here, a light barrier is provided around the row of bales. Upon interruption of the light barrier the opening rollers are stopped. A drawback of this or any similar arrangement resides in the large size of the fenced off area, and thus, the freedom of movement of the operating personnel is exceedingly limited. Although measures are taken for keeping the protected area as small as possible (switching between two monitoring areas), in general an excessively large monitoring area is covered, which can lead to unnecessary work interruptions. There is also a risk that the light beam monitoring the danger area can be stepped over by personnel, or passage under the same is possible. In addition, personnel located in the monitoring area prior to switching on of the means are not detected. The system is also based on a precise arrangement of the mirrors or reflectors and is consequently fault-prone (deformation/shifting of the reflectors). Also, there exists a relatively great probability of sounding a false alarm, since intrusion past the barrier or fence constitutes an actual danger in only a limited number of instances, and thus, for instance, the textile machine is unnecessarily shutdown too often. A further drawback of such prior art apparatuses is that large foreign bodies, even humans, located at the region of the row of bales, cannot be detected prior to turning on the safety barrier.
In order to prevent such drawbacks, there have been disclosed safety equipment which use mechanical and/or sensor means for fencing off or shielding only the immediate vicinity of the potentially dangerous opening rollers. Here, the barrier or fence moves in conjunction with the machine frame and the opening roller. Such type safety equipment has been disclosed, for example, in the commonly assigned European Published Patent Application No. 90810018.3, published Jul. 25, 1990 under European Published Patent No. 379,465. The therein disclosed safety equipment seals off by mechanical and/or sensor means all locations where the danger region beneath the opening member is not obturated by the floor, by mechanical components or the bales, resulting in complete closing off of such region. However, since fencing off of this dangerous region by the floor and the bales is dependent to a great extent upon the configuration of the row of bales, the additional barriers, especially the sensors, must be coordinated to the shape of the row of bales, and this bale row shape, in the case of irregular bales in the bale row, continually changes during movement of the bale opening machine. Even though such disclosed prior art safety equipment affords a considerable degree of operational safety along with maximum degree of mobility of the operating personnel, still such safety equipment is quite complicated in design and expensive in construction, since it must be controlled as a function of the actual shape of the row of bales which is momentarily being opened. Without such a control, bales or parts of bales would be construed as an unauthorized intrusion into the monitored area. Hence, complicated control mechanisms are required, which not only renders the machine construction more complex, but, in turn, results in new safety risks.
Reverting now again more specifically to the potentially encountered risks at such bale opening machines, these may be basically classified as follows: Firstly, there exists the risk of the bales being too narrow, that is to say, bales not extending over the full width of the opening member. In this case there is a so-to-speak projection of the opening roller beyond the textile fiber bales to be worked. There is also a risk in the lateral regions of the opening member, that is to say, on the sides in the advance direction of the opening member. Difficulties are encountered in fitting protective means to such bale openers. Particularly in the case of mechanical protective means the problem arises that they do not engage with the bales or may collide with other mechanical means.
Problems also occur with sensory protective means, because, for example, modifications of the bale profile or bales are detected as penetrating objects. Thus, in the case of the known sensory protection concepts, either the bale opener (including the complete bale row) is monitored as an entity, or the sensors only detect limited areas over the bales, so that once again only an incomplete protection is provided.
Another protective device is known from German Published Patent Application No. 3,733,972. A live electric conductor is passed around the opening member and generates an electromagnetic field. The field change brought about by an approaching person is established by a control device, which then operates a limit switch. However, as the arrangement possibilities of the conductor are limited, this device can only cover a limited area, which is fundamentally restricted to a zone above and to the side of the opening for the opening rollers. It is particularly disadvantageous that a person penetrating from below into the danger area may not even be detected, or the measuring field must be extended to such an extent that once again zones around the opening member are also detected, which leads to unnecessary interruptions. It does not solve the problem that bales are detected by the sensor if the field is extended. Thus, from the constructional side, only a limited area over the bales can be monitored, which means that protection remains incomplete. The self-monitoring question is also unsolved.
In addition, mechanical protective flaps or covers for opening rollers are known. These are located within the opening member casing or housing. With more recent constructions of opening members equipped with several, for example, two opening rollers, such a means cannot be realized for space reasons.
It has been found that the actual danger area for a bale opener is relatively small and essentially only consists of the zone or area below the opening member or opening rollers. Therefore the monitoring zone should correspond to this danger zone or area, particularly if corresponding safety or protective means are located outside the opening member casing or housing. Account is not taken of this by the known means.